All the oxidized_copper should be "Oxidised" not "Oxidized".

en_nz uses -ise not -ize, so as well as this, stuff like the "Redstone Randomizer" should probably be "Redstone Randomiser", Fertilizer -> Fertiliser, etc.

"Color" should be "Colour"

"Gray" should be "Grey"

Chiseled should also be Chiselled

generally, NZ spelling follows British English rather than American English, and while it doesn't really make much gameplay difference, what's the point of even having a translation if it's incorrect, and vanilla parity is important

mind making a PR?